You make my point.
You are an adult. Your body has different needs than a growing infant or child. You had the proper nutrition you needed growing up.
Malnutrition among the children of vegetarians and vegans was a growing epidemic in the US until the CDC, AMA and others finally got some cooperation from major national vegan and vegetarian advocacy groups to get the word out on the need for a proper diet or supplements for infants and children put on restrictive diets.
It has also been shown by recent studies that problems like lactose intolerance can be passed on to unborn children from vegan mothers who never had a problem drinking milk because they grew up drinking milk.